(S)-4-[(S)-3-((S)-4-hydroxy-6-aza-spiro[2.5]oct-6-yl)-1-hydroxymethyl-propyl]-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester 、
异氰酸乙酯 在
ice 、 SiO2 、
二氯甲烷 、
methanol-dichloromethane 作用下,
以
乙腈 为溶剂,
反应 88.0h,
以to afford the title compound (33 mg, 45%)的产率得到(S)-4-[(S)-1-ethylcarbamoyloxymethyl-3-((S)-4-hydroxy-6-aza-spiro[2.5]oct-6-yl)-propyl]-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester